Application of Microplasma for $\hbox {NO}_{\rm x}$ Removal

In this paper, microplasma is investigated, which occurs between the narrow gap of the electrodes covered with dielectric materials. The discharge gap is set on the order of micrometers by changing a spacer from 0 to 100 mum. In this paper, the characteristics of microplasma, such as discharge voltages, discharge currents, and discharge power that is obtained with the help of Lissajous figures, and the relationships between these electric characteristics are presented. The characteristics of ozone generation by a microplasma electrode are investigated. Treatment by microplasma for the simulated exhaust gas, which contains NO_x and C₃H₈ as a role of HC and CO, is estimated experimentally. In the absence of O₂, the exhaust gas is decomposed by nitrogen atomic species in particular. In the presence of O₂, it is decomposed by nitrogen atomic species and oxidized by ozone. By-product analysis of treated gases is carried out by Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry. When HC, NO_x, and N₂ are included in the simulated exhaust gas, HCN, N₂O, and CH₄ are confirmed as by-products of the microplasma treatment.